Key actuated switch

ABSTRACT

Switch means incorporating means to energize an electric circuit upon use of a key of predetermined characteristics but which will energize an alarm system upon use of an improper key, or fail to work at all.

United States Patent Schwendeman, Jr.

KEY ACTUATED swlrcrr Inventor: Wayne C, Schweiideman, Jr., 4708 Garfield, Lisle, 111. 60532 I Filed: Nov; 1, 1971 Appl.No.: 194,372

uQs. Cl. .Q "lass/206, 70/413, zoo/61.66 1m. ci. ..'..,...H01h 27/00, l-lOlh 27/06 [151 3,705,369 [451 Dec, 5, 1972 I [-56] References Cited UNITED STATES PATENTS 2,767,278 10/1956 Collins .....s3s/206 Primary Examiner-Roy N. Envall, Jr. Attorney-Elmer L. Zwickel [57] ABSTRACT Switch means incorporating means to energize an electric circuit upon use of akey of predetermined characteristics but which will energize an alarm system upon use of an improper key, or fail to work at 'all.

4 Claims, S Drawing Figures 15 '5 a I I ,4 y Ill E 1 i "12 l fixed therein.

I lock cylinder.

body, hereincalled lock cylinder, having mounted about its cylindrical wall a plurality of magnetically ac tuated reed switches, one or more of which is electrically connected, for example, to the ignition circuit of an automobile and the others to an alarm system which may be visible oraudible. I The key is comprised of a non-magnetic dowel having embedded in it, at a predetermined location, a permanent magnet. The key has a spiral groove extending along its length which cooperates with an internal pin or studin the lock cylinder. When a proper key is used, the spiral groove and stud cause the key to rotate and in such'inanner' that the switches for the alarm are bypassed by the magnet which is ultimately brought into register with the switch or switches for the ignition circuit. 1 i

It is therefore an object of the invention to provide an assembly of the character referred to.

Another object is to provide a magnetic key for selective association with an electric switch.

Another object is to provide a key fabricated from material'non-magnetic and having a permanent magnet Another object is to providea keythat'is cylindrical in cross section and has means therein to cause it to rotate while being inserted into alock cylinder.

' Another object is to provide a lockcylinder and an associated key, incorporating cooperative means to cause the key to rotate while being Another object is to plurality of electric switches some of which are operable to activate an alarm when an improper key is inserted into the lock cylinder. t

Other objects and advantages of the invention will become apparent with reference to the following description and accompanying drawing.

In the drawing:

FIG. 1 is an axial sectional view of the lock cylinder.

FIG. 2 is a side elevational view of the key.

inserted into the provide a lock cylinder with a of these switches, for example, the switch 13a, is connected In the electrical circuit to the starter-ignition system of a vehicle whereas, the remaining switches 13b and 130 are connected in parallel in the electrical circuit to analarm device such as the buzzer 14 shown. This is best illustrated in FIG. 5. a

The key 12 is fabricated from non-magnetic material in cylindrical form and of a size to fit snuglybut slidably in the lock cylinder 11. It has formed in its surface from end to end, a spiral groove or key-way 15. It also carries adjacent its lead-in end a permanent magnet 16 that is embedded in its body.

When the key 12 is to be inserted into the lock cylinder 11, the key-way is placed in register with a stud, or pin 17, on the inside surface of the entrance end of the lock cylinder so that as the key is pushed into the lock cylinder it is rotated. The magnet 16 is so located circumferentially on a proper key'that when the key is thrust totally into the lock cylinder the magnet will be brought into register with the switch 13a so as to cause same to close and energize the circuit to the ignition coil 18. The remaining switches 13b and 13c are so located circumferentially that the magnet never registers with either of them during key insertion or withdrawal hence the alarm'system is not actuated. Should an improper key be inserted, one or the other of said switchesl3b or 130 will be closed by the-magnet and the alarm 14 activated or gister with 13a. v

- The structure has been described asapplicable to the ignition system of a motor vehicle, but it'should be understood. that the switch can be used in any electrical circuit, such as an alarm system for a door, or the ignition or starter system for other types of vehiclesor motors. i

. Although I have described a preferred embodiment of the invention, in considerable detail, it willbe understood that the description thereof is intendedto be illustrative, rather than restrictive, as details of the structure may be modified or changed without department from the spirit or scope of the invention. Ac-

the magnet will not-re- I cordingly, I do not desire to be restricted to the exact FIG. 3 is a view showing the key insertedinto the the lock, a starter ignition coil and an alarm device.

Referring to the exemplary embodiment of the invention as shown in the accompanying drawings, the lock assembly includes a lock-cylinder 11 and a key 12.

The lock cylinder preferably is comprised of a hollow cylindrical body open at one end and having a plurality I manent magnet carried by said key, a spiral key-way slot in said key, and a pin on said lock cylinder engaged in said key-way and effective to cause the key to rotate during its insertion into the lock cylinder to carry the magnet into close association with a selected one ofthe switches for closing same when the key is fully posi tioned in said lock cylinder.

2. The switch recited in claim 1, in which the switches are mounted on the lock cylinder.

3. The switch recited in claim 1, in which the key comprises a solid cylindrical body.

4. The switch recited in claim 3, in which the magnet is embedded in the cylindrical body. 

1. An electric switch comprising a lock cylinder, a plurality of normally open magnetic switches spaced along and surrounding said lock cylinder, a key, a permanent magnet carried by said key, a spiral key-way slot in said key, and a pin on said lock cylinder engaged in said key-way and effective to cause the key to rotate during its insertion into the lock cylinder to carry the magnet into close association with a selected one of the switches for closing same when the key is fully positioned in said lock cylinder.
 2. The switch recited in claim 1, in which the switches are mounted on the lock cylinder.
 3. The switch recited in claim 1, in which the key comprises a solid cylindrical body.
 4. The switch recited in claim 3, in which the magnet is embedded in the cylindrical body. 